Probably the most important aspect of the Indian lutes is the flat and wide table-shaped bridge. The tanpura is an instrument that is designed to create a controlled cloud of overtones that form the base and background to the music. The main process of creating these overtones comes from the flat bridge and the process called "jawari". The name "Jawari" comes from the word "Jiwa" which literally means soul. In Indian music, jawari is used when describing the quality of a tone, not its musical perspective, but more in a sense of its acoustic quality. For example, some strings have a harsh, shrill, twangy sound and others sound dull and dead. Jawari is the process by which the instrument maker or repairer can shape the flat rounded bridge to produce the correct and required sound, not too shrill or too dull, but according to the musicians personal taste and the instruments' requirements. The overtones are clearly audible and enhanced with a good jawari.
Nowadays the art of jawari is a dying profession in India, and there seems to be only a handful of instrument makers and repairers who have mastered the technique. It is an art that takes many years of practice. The jawari has given Indian music and its instruments a refined profoundness in its conception of sound aesthetics.
Music as we know it has been developed from the core of the note or tone itself. Essentially a note is a vibration where the main tone that we hear, the fundamental, is only one of many tones that are present and vibrating at that given moment. These other tones, or overtones as we call them are mostly inaudible to the human ear. Western musical instruments usually find ways of dampening the overtones finding them ugly and unwanted, thereby using thin upright bridges to lessen the chances of hearing them. Whereas in India, overtones have a more prominent and profound role to play. The design of the flat bridge on the Indian lutes enables the overtones to become audible and to play a crucial role in the overall conception of sound quality.
Music in either the western or eastern hemispheres depends on overtones as the basis of the note and tone material used. A scale is nothing more than a collection of overtones in a specific order. Chinese legend has it that in the year 2697 BC, Lin Lun discovered by blowing hard over a bamboo pipe that he was able to create the quint as an overtone. He made a second pipe 1/3 shorter than the first pipe and tuned to the first fifth. Repeating the process by blowing hard over this pipe he was able to produce the fifth once again. Continuing this procedure he produced 12 quints which together created the chromatic scale, the so-called circle of fifths:
C – G – D – A – E – B – F# - C# - G# - D# - A# - E# (F) - B# (C)
Years later in Greece, Pythagoras created toneladders and theories based on the same principles as Lin Lun. We can see that these principles form the essence of the octave which is the basis of music as we know it today. We can also conclude that the octave is made up of overtones that are directly (sonant) and indirectly (dissonant) related to each other, and that the whole scale is essentially originating from one note.